From 012598880cf69a6a4d4d495c78e40ab4abb4eb39 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Sat, 22 Nov 2014 15:44:43 +0100 Subject: Implement test for merkle tree malleability in CPartialMerkleTree This is a check that is mentioned in BIP 37, but never implemented in the reference code. As Bitcoin Core so far never decodes partial merkle trees, this is not a problem. But perhaps others use the code as a reference. --- src/merkleblock.cpp | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'src/merkleblock.cpp') diff --git a/src/merkleblock.cpp b/src/merkleblock.cpp index 8618e355d7..0500cfde88 100644 --- a/src/merkleblock.cpp +++ b/src/merkleblock.cpp @@ -93,10 +93,16 @@ uint256 CPartialMerkleTree::TraverseAndExtract(int height, unsigned int pos, uns } else { // otherwise, descend into the subtrees to extract matched txids and hashes uint256 left = TraverseAndExtract(height-1, pos*2, nBitsUsed, nHashUsed, vMatch), right; - if (pos*2+1 < CalcTreeWidth(height-1)) + if (pos*2+1 < CalcTreeWidth(height-1)) { right = TraverseAndExtract(height-1, pos*2+1, nBitsUsed, nHashUsed, vMatch); - else + if (right == left) { + // If the left and right branch should never be identical as the transaction + // hashes covered by them must be unique. + fBad = true; + } + } else { right = left; + } // and combine them before returning return Hash(BEGIN(left), END(left), BEGIN(right), END(right)); } -- cgit v1.2.3